Motor retrofit for scooter

ABSTRACT

The present invention is a retrofit kit that mechanically attaches to a push scooter. The retrofit kit converts the push scooter into an electrically driven scooter. The retrofit kit includes a bracket that may attach to the rear fork of the scooter so that the existing components of the scooter do not need to be modified. Components of the retrofit kit can also be used to originally manufacture the scooter. A motor assembly and a battery are supported on the scooter. The motor assembly includes a roller that frictionally engages and drives the rear wheel of the scooter when an individual activates a throttle assembly. In another embodiment, the motor assembly is located between a floorboard and a rear wheel and a foot brake is located aft of the rear wheel.

PRIORITY CLAIM

[0001] This application claims priority from U.S. Provisional PatentApplication No. 60/385,698, filed on Jun. 4, 2002, and this applicationclaims priority from U.S. Provisional Patent Application No. 60/384,053,filed on May 29, 2002. Each of these provisional patent applications isbeing incorporated herein by this reference.

FIELD OF THE INVENTION

[0002] The present invention generally relates to a device that convertsa manual push scooter into an electrically powered scooter. Morespecifically, an embodiment of the present invention is a retrofit kitthat includes a motor assembly to frictionally drive a wheel of thescooter.

BACKGROUND OF THE INVENTION

[0003] Most scooters are designed and manufactured primarily forrecreational use. Manually powered scooters are well known as efficientmeans for transportation. Such scooters are propelled by the rider usinga single stride with one leg, while the other leg and foot aremaintained in contact with the rider platform. The front wheel of thescooter is steered by a handle bar that is also connected to theplatform. Most commonly, a push scooter has a foot brake locatedproximate to and above the rear wheel. A rider may slow the scooter downby depressing the foot brake downward, bringing the foot brake intocontact with the rear wheel and frictionally slowing the rotation of therear wheel.

[0004] An example of a folding collapsible push scooter is shown inFIG. 1. The scooter 10 includes a footboard 11, a rear wheel 14, a footbrake 16, a front fork assembly 18, a collapsible connecting bar 22, afront wheel 24, and a handle bar 26. The footboard 11 is the main areawhere the rider stands while driving or operating the scooter. Thehandle bar 26 is mounted to and supported by the connecting bar 22. Theconnecting bar 22 is pivotally mounted onto the fork assembly 18,allowing a rider to turn the front wheel 24 left and right. Theconnecting bar 22 may telescope up and down, allowing the rider toadjust the height of the handle bar 26. The rear wheel 14 is securedrelative to the footboard 11 by a rear axle 30 mounted through a rearfork 32 extending rearwardly from footboard 11. The foot brake 16, asshown in FIG. 1, is commonly located over the rear wheel 14, so that therider may easily keep one foot on the footboard 11 while the other footoperates the foot brake 16.

[0005] One reason the scooter is so popular is that the scooter can befolded into a compact structure, making it easy to carry and store whennot in use. For example, the fork assembly 18 may pivot between anoperative or extended position, as shown in FIG. 1, and a non-operativeor collapsed position where the connecting bar 22 is substantiallyparallel to the footboard 11.

[0006] Electrically powered scooters have begun to replace pushscooters. An electric scooter eliminates the need for the rider to pushon the ground to propel the scooter forward. Instead, the rear wheel iselectrically driven when a throttle assembly, commonly located on thehandlebar, is activated by the user. A manual foot brake is stillcommonly used to frictionally slow the scooter down. Over the years, theelectrically powered scooter has become the preferred type of scooter.

[0007] There are still many manual push scooters on the market today.For example, the Razor™ scooter has several models of manual pushscooters such as the RZ Cruiser™ and the RZ Ultralite™. Such scootersare being used today. Owners of a manual push scooter may not wish tobuy a new, more expensive electric scooter. Thus, there is a need toprovide an apparatus to convert existing manual push scooters intoelectrically powered scooters at a low cost.

SUMMARY OF THE INVENTION

[0008] An aspect of the present invention is to provide an apparatusthat can attach to a manually powered scooter and convert the manualpush scooter into an electrical scooter. An embodiment of the presentinvention connects to the rear fork of the manually powered scooter.Once attached, a roller frictionally engages and drives the rear wheelto propel the scooter.

[0009] Another aspect of the present invention is to attach an apparatusto a scooter that will not require modifying any of the existingcomponents. An embodiment of the present invention does not reduce theexisting footboard space that a user stands on when riding the scooteror alter the existing foot brake system of the scooter.

[0010] In a further aspect of the invention, the motor is mountedbetween a floorboard and a rear wheel, with a foot brake located aft ofthe motor.

[0011] Yet another aspect of the present invention is to allow a user toelectrically control the speed of the scooter. An embodiment of thepresent invention includes a throttle assembly that mounts onto thehandlebar of the scooter. In this embodiment, a throttle handle iselectrically connected to a motor assembly and a battery. The speed ofthe motor is controlled by activating the throttle handle.

[0012] Still another aspect of the present invention is to provide anapparatus that has easily replaceable parts. An embodiment of thepresent invention has a removable friction roller that can be replacedwhen it degrades or wears out. Another embodiment of the presentinvention has a removable battery housing so that a battery storedwithin the housing can be conveniently removed and recharged.

[0013] Another embodiment of the present invention has a motor cut-offswitch that will prevent the rider from burning out or destroying themotor. In one embodiment, the motor is electrically isolated from thebattery and throttle assembly when the foot brake is activated.

[0014] A further embodiment of the present invention is to allow a riderthe flexibility to either manually push the scooter or electricallypropel the scooter. One embodiment has a roller positioning mechanismfor holding the roller against the rear wheel or maintaining the rolleraway from the rear wheel.

[0015] Further, an embodiment of the invention includes a robustattachment device to secure the battery and also the motor to thescooter.

[0016] Other aspects and features of the invention can be found in thespecification, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a perspective view of a folding collapsible pushscooter, according to the prior art.

[0018]FIG. 2 is a perspective view of an embodiment of the presentinvention attached to the push scooter shown in FIG. 1.

[0019]FIG. 3 is a partial exploded view of the embodiment of the presentinvention shown in FIG. 2.

[0020]FIG. 4 is an exploded view of an embodiment of the motor assemblyof FIG. 3, according to the present invention.

[0021]FIG. 5 is a perspective view illustrating the roller removed fromthe motor assembly of the embodiment of FIG. 2 of the invention.

[0022] FIGS. 6A-6C, FIG. 6A is a top view of the embodiment of FIG. 2 ofthe present invention in an engaged position; FIG. 6B is a side partialcutaway view along line C-C in FIG. 6A; FIG. 6C is a sectional view ofarea D indicated in FIG. 6B.

[0023] FIGS. 7A-7C, FIG. 7A is a top view of the embodiment of FIG. 2 ofthe present invention in a disengaged position; FIG. 7B is a sidepartial cutaway view along line B-B shown in FIG. 7A; FIG. 7C is asectional view of area E shown in FIG. 7B.

[0024]FIG. 8 is a perspective view of an alternate embodiment of themotor assembly of the invention.

[0025]FIG. 9 is a side view of the alternate motor assembly of theinvention shown in FIG. 8.

[0026]FIG. 10 is a sectional view of the motor assembly of the inventionshown in FIG. 8.

[0027]FIG. 11 is a perspective view of the internal components of themotor assembly of the invention shown in FIG. 8.

[0028]FIG. 12 is a perspective view of the internal components of themotor assembly of the invention shown in FIG. 8 in a disassembled state.

[0029]FIG. 13 is an exploded perspective view of a battery and a batterymount of an embodiment of the invention.

[0030]FIG. 14 is a perspective view of a battery of the embodiment ofFIG. 13 of the invention mounted on the battery mount shown in FIG. 13.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0031] The present invention will be described in reference to FIGS.2-14. FIG. 2 illustrates the retrofit kit 100 attached to the rear fork32 of the scooter. The retrofit kit 100 includes a mounting bracket 102,a battery housing 104 and a motor assembly 106. The mounting bracket 102is the main support for both the battery housing 104 and the motorassembly 106. In a preferred embodiment, as shown in FIG. 2, theretrofit kit 100 mounts on the rear fork 32 and extends from the rear ofthe scooter. This design does not require modifying any of the parts ofthe scooter, and does not interfere with the operation of any of theparts of the scooter. For example, the mounting bracket 102 forms aroundthe rear tire 14 and the foot brake 16 when mounted to the scooter. Asthe mounting bracket 102 is the main structure to support all thecomponents of the retrofit kit 100, the mounting bracket 100 should be arigid structure. The mounting bracket 102 may be manufactured frommaterials such as, but not limited to, aluminum, steel, and stainlesssteel. It is within the scope of the present invention for the mountingbracket 100 to be manufactured from other materials.

[0032] The mounting bracket 102 secures to the scooter by two flanges108. In one embodiment, each flange 108 has a “U”-shaped channel 110located on the interior of each end 111. The width of each “U”-shapedchannel 110 is preferably slightly larger than the width of each rearfork 32. Additionally, the distance between the two flanges 108 ispreferably substantially similar to the width between the rear forks 32.These dimensions allow each “U”-shaped channel 110 to slide over theoutside surface of the rear fork 32, yet at the same time provide arigid connection between the bracket 102 and the rear fork 32. As shownin FIG. 2, the platform 103 that the battery housing 104 is secured tois horizontal. However, it is within the scope of the present inventionfor the platform 103 to be at an angle when the bracket 102 is mountedon the scooter.

[0033] The mounting bracket 102 is held stationary relative to thescooter by the rear axle 30. That is, the mounting bracket 102 cannotslide onto the rear fork 32 while the rear axle 30 is in place. Toinstall the bracket 102, a user should first remove the rear axle 30.Removing the rear axle 30 disengages the rear wheel 14 from the rearfork 32. After removing the rear axle 30, the user should align thechannels 110 with the rear forks 32 and slide the flanges 108 over therear forks 32 until the bore 112 in the flange 108 aligns with the axlehole in the rear fork 32. Once the mounting bracket 102 is aligned withthe rear fork 32, the rear axle pin 30 may be re-inserted. In effect,the rear axle 30 functions as the rotation axis for the rear wheel 14and prevents translation of the bracket 102 relative to the scooter.

[0034] The power for the retrofit kit 100 is supplied by a battery 156(see FIGS. 6B and 7B). The above battery housing 104 encases the battery156. The battery housing 104 prevents an individual from accessing andtouching the battery terminals. In the embodiments shown in FIG. 2 asdescribed above, the bracket 102 has a platform 103 that the batteryhousing 104 mounts to, and rests upon. As shown in FIG. 3, an alternateembodiment of the battery housing 104 is a two-piece container. By wayof example only, the housing 104 may be manufactured from ABS plastic.In one embodiment, the two halves of the housing are ultrasonicallywelded together to form a single unit. However, in alternateembodiments, the two halves of the housing 104 may be fastened togetherby any method as long as the halves can be repeatedly separated (e.g.,fasteners, clamps or bolts). Methods to attach and repeatedly separatetwo halves of a housing are known to those skilled in the art. In theembodiment shown in FIG. 3, the housing 104 has an access hole (notshown) in the side or bottom to allow the cable 162 (FIG. 2) to enterthe battery housing 104 and electrically connect to the battery 156. Inone embodiment, the battery 156 is secured within the housing 104 sothat the battery 156 will not move or slide around within the batteryhousing 104 during operation of the scooter. For example, scooters aredriven on many different types of terrain, such as on smooth streets andbumpy sidewalks. The housing 104 is preferably fastened to the platform103 to prevent the housing 104 from falling or sliding off the platform103 during operation of the scooter. By way of example only, the housing104 may be attached to the platform 103 by a latch, a bolt or any othertype of fastening mechanism. Alternate embodiments can include afastening plate 105 that attaches to the housing 104 and the platform103 (see FIG. 3). In one embodiment, the fastening plate 105 and thehousing 104 have a quick-release mechanism, allowing the user to easilydisconnect the plate 105 or the housing 104 from the bracket 102.

[0035]FIG. 4 illustrates one embodiment of the components of the motorassembly 106. In the embodiment shown in FIG. 4, a motor housing,comprised of a first half 120 and a second half 122, encloses andsupports a motor 114, a roller 116 and a torsional spring 118. The firsthalf 120 of the motor housing has a motor shaft bore 124, a supportcolumn 126, and a pulley shaft bore 130. When the motor housing isassembled, the bore 124 aligns with the motor shaft 135. The motor shaft135 passes through the bore 124 and extends out of the motor housing.The support column 126 has a cavity that a first end 127 of the pivotshaft 128 extends into such that the pivot shaft 128 can rotate withinthe support column 126. In the embodiment shown in FIG. 4, the pulleyshaft bore 130 is located below the pivot shaft 128 and aligns with thesecond timing belt pulley 132.

[0036] The second half 122 of the motor housing is a mirror image of thefirst half 120 and includes a motor support, a support column 138, andan axle bore 140. The motor support aligns with the stationary motorshaft 135. Thus, the motor 114 is supported by the motor shaft bore 124and the motor support 134 when the first half 120 and second half 122are secured together. The support column 138 has a cavity similar to thesupport column 126 for accepting the second end 129 of the pivot shaft128 and the bore 140 aligns with, and supports, the axle bearing 142.

[0037] The rotating shaft 135 of the motor 114 extends through the bore124 of the first section 120 and engages a first timing belt pulley 131.The timing belt pulley 131 is secured to the shaft 135 and thereforerotates at the speed of the shaft 135. In operation, the motor shaft 135drives the first timing belt pulley 131 in a clockwise direction. By wayof example only, a motor suitable for the motor assembly 106 ismanufactured by Mabuchi Motor, Model No. RS-775 or RS-500 series. Thefirst timing belt pulley 131 drives the second timing belt pulley 132 bya timing belt 142 that frictionally engages both the first pulley 131and the second pulley 132. Thus, the first pulley 131 and second pulley132 rotate in the same direction.

[0038] The two pulleys 131 and 132 operate as a gear reduction mechanismso that the roller 116 will rotate at a slower speed than the motorshaft 135. For example, and as shown in FIG. 4, the diameter of thepulley 132 is larger than the diameter of the pulley 131. As previouslymentioned, the pulley 131 rotates at the speed of the motor shaft 135.In a preferred embodiment, the diameter of the second pulley 132 is fiveto eight times larger than the diameter of the first pulley 131.Accordingly, the second pulley will rotate five to eight times moreslowly than the first pulley 131.

[0039] The second pulley 132 has a shaft 133 that extends through thebore 130 and into the motor housing when the motor assembly 106 isassembled. The bore 130 is larger than the shaft 133 so that the pulley132 may rotate freely. In one embodiment, the shaft 133 is maintainedsubstantially parallel to the motor shaft 135. A bearing 150 is pressfit into a bearing seat (not shown) located within the outer pulley 132so that the bearing 150 and the pulley 132 rotate as a single object. Adrive belt 143 connects first pulley 131 and second pulley 132.

[0040] In the embodiment shown in FIG. 4, the bearing is rotatablymounted onto a stem 152 extending from the protective cover 154.However, in alternate embodiments, the pulley 132 can mount directlyonto the stem 152. In either case, the central axis of rotation of thepulley 132 is the stem 152. The protective cover 154 attaches to thefirst half 120 of the motor housing and remains separated from the outersurface of the motor housing so that it does not interfere with theoperation of the pulleys 131 and 132 or the timing belt 142.

[0041] The roller 116 has a cavity to engage the shaft 133. As shown inFIG. 4, the shaft 133 has a cruciform shape. However, in alternateembodiments, other interlocking or keyed shapes can be used. The cavityof the roller 116 should be shaped similarly to the shaft 133 and havesubstantially the same diameter such that the roller 116 and the shaftrotate as a single unit and that the roller 116 does not slide inresponse to, or independent from, the shaft 133. Thus, the roller 116will rotate at the same speed as the pulley 132.

[0042] In the embodiment shown in FIG. 4, the roller 116 preferablyremains in a substantially horizontal position at all times. To helpmaintain this position in one embodiment, the roller 116 is supported atboth ends. As previously mentioned, one end of the roller 116 is mountedon, and rotates about, the stem 152. An axle 142 extends from the otherend of the roller 116. The axle 142 extends through, and is rotatablyseated within, the bore 140 and a bearing 144 is seated within thebearing seat 141 of the axle 142. In one embodiment, the bearing 144 ispress fitted into the bearing seat 141. The bearing engages a stem 148that protrudes from the access cover 146. Similar to the bearing 150,the bearing 144 is rotatably secured to the stem 148 so that the roller116 may rotate freely. Accordingly, the roller 116 is ultimatelysupported by the stems 148 and 152. The stems 148 and 152 are alignedalong a concentric horizontal axis so that the roller 116 remains in asubstantially perpendicular position in relation to the rear wheel 14when the roller is in both the power-assist mode and the free-wheel mode(both described later).

[0043] In the power assist mode, the roller 116 frictionally contactsand drives the rear wheel 14 of the scooter. The continuous contactbetween the roller 116 and the rear wheel 14 will tend to wear theroller 116 down over time. The roller 116 is preferably manufacturedfrom a material that will not easily degrade. The roller 116 may bemanufactured from materials such as, but not limited to, steel oraluminum, to increase the life of the roller 116, or also rubber,plastic, a polymer or an elastomeric material which, preferably, issofter than the rear wheel. The roller 116 has a track or channel 117.In one embodiment, the track 117 is preferably shaped substantiallysimilar to the contour of the rim of the wheel 14. For example, thetrack 117 is substantially “U”-shaped to mirror the shape of the wheel14 shown in FIG. 1. Since the roller 116 will experience wear and tearfrom the frictional contact with the rear wheel 14, the roller 116 mayneed to be replaced from time to time.

[0044] As shown in FIG. 5, the motor assembly 106 is been designed sothat the roller 116 can be easily replaced by the rider without havingto remove the entire motor assembly 106 from the bracket 102. To replacethe roller 116, the user can first place the scooter in the free-wheelmode (described hereinafter) by decoupling the roller 116 from the rearwheel 14. The cover 146 can then be removed to access the roller 116. Inone embodiment, and as shown in FIG. 5, the cover 146 is secured to themotor assembly 106 by four screws. Once the cover 146 is removed, anindividual can remove the worn-out roller by sliding the roller 116 offthe pulley shaft 133 and out of the motor housing 106. A new roller 116can then be placed into the motor assembly 106 and onto the shaft 133.After inserting a new roller, a user can replace the bearing 144 backinto the bearing seat 141 and fasten the cover 146 to the motor assembly106.

[0045] The scooter can be operated in a free-wheel mode and apower-assist mode. When the roller 116 is placed in the power-assistmode (see FIGS. 6B-6C), the track 117 of the roller 116 contacts therear wheel 14 along its outer surface 15. The shape and size of the rearwheel 14 will vary depending on the manufacturer and model of thescooter. For example, some scooters, such as the Razor™ models, usesmaller wheels having a diameter of approximately five inches. Otherscooters, such as a few models designed by The Sharper Image™, uselarger wheels having a diameter of nine inches. Thus, the shape and sizeof the roller 116 can vary to accommodate the specific shape of the rearwheel 14.

[0046] In one embodiment, there is a large contact area between theroller 116 and the rear wheel 14 to frictionally drive the rear wheel14. The frictional force is proportional to the contact area sharedbetween the two surfaces. The larger the frictional force createdbetween the roller 116 and the rear wheel 14, the more efficiently theroller 116 will drive the rear wheel 14. A larger frictional force willalso prevent the roller 116 from slipping while driving the rear wheel.However, it is noted that the final linear speed of the rear wheel isindependent of the size of the rear wheel.

[0047] A rider should still have the option to manually push thescooter. For example, if the battery 156 expires while riding thescooter, it would be beneficial if the rider could manually push thescooter and not have to overcome the resistance created by the roller116 remaining in contact with the rear wheel 14. The scooter cantherefore operate in a free-wheel mode.

[0048] The torsional spring 118, mounted on the shaft 128, rotates toeither hold the roller 116 against the rear wheel 14 (power-assist mode,FIGS. 6A-6C) or keep the roller 116 away from the rear wheel 14(free-wheel mode, FIGS. 7A-7C). The shaft 128 is manually moved betweenthe two positions by a lever (not shown) that is pivotally attached toand extending from the second half 122 of the motor housing 106. Thelever is mechanically attached to the pivot shaft 128 and can be movedbetween a power-assist mode or free-wheel mode location. The lever canbe “locked” into either position. Such engagement and locking mechanismsare well known in the art.

[0049] In the power-assist mode the roller 116 is held against the rearwheel 14 by the force from the torsional spring 118 FIGS. 6A-6C). FIG.6B is a partial cross-sectional view of the motor assembly 106, alongextension line C-C in FIG. 6A. As shown in FIG. 6B, the roller 116 isheld against the rear wheel 114. In this position, the roller 116 willfrictionally drive the rear wheel 14 when the throttle assembly 160 (tobe described later) is activated. FIG. 6C illustrates a more detailedview of the roller 116 engaging the rear wheel 14, as shown in area D inFIG. 6B. The roller 116 is spring-biased in this position during thepower-assist mode. By activating the throttle assembly 160, the roller116 will rotate and drive the rear wheel 14, propelling the scooterforward.

[0050] If the user wishes to manually push the scooter, the user canselect the free-wheel mode. The user can mechanically decouple theroller 116 from the rear wheel 14 by rotating the housing against 104the torsional spring 118 away from the rear wheel 14. This action isaccomplished by rotating the lever in the opposite direction that wasrequired to place the scooter in the power-assist mode. By decouplingthe roller 116 from the rear wheel 14, the rear wheel 14 may rotatefreely about the rear axle 21. While the scooter is in the free wheelmode, the roller 116 is held away from, and is not in contact with, therear wheel 14. FIGS. 7A-7C illustrate that the roller 116 is held awayfrom the rear wheel 14 at all times during the free-wheel mode.

[0051] The retrofit kit 100 includes a throttle assembly 160 thatelectronically controls the rotation of the roller 116 (see FIG. 2). Thethrottle assembly 160 includes a cable 162 and an acceleration handle164. The cable 162 is electrically connected between an accelerationhandle 164 and the battery 156. In one embodiment, the cable 162preferably travels down the connecting bar 22, across the side of theplatform 10 and along the mounting bracket 102 to the battery 156. Inone embodiment, the cable 162 is secured to the connecting bar 22, theplatform 10 and the mounting bracket 102 to prevent the cable 162 fromgetting caught or snagged on a passing object. In an alternateembodiment, the cable 162 is secured to the side or bottom of theplatform 10 so that the user will have a flat surface to stand upon.

[0052] In one embodiment, the acceleration handle 164 is mounted to thehandlebar 26 so that the rider may conveniently control the speed of thescooter while standing on the platform 10. To activate the motor 135 andthus the roller 116, the acceleration handle 164 may be pulled towardsthe handlebar 26. When the handle 164 is pulled towards the handlebar26, the roller 116 begins to rotate and drive the rear wheel 14. In oneembodiment, the closer the acceleration handle 164 is pulled towards thehandlebar 26 the faster the motor shaft 135 will rotate. Releasing theacceleration handle 164 to its “normal” position will electricallyisolate to the motor 114 from the battery 156 and the motor will nolonger drive the scooter. Such speed control is well known in the art.Positioning the acceleration handle 164 on the handlebar 26 allows auser to steer the scooter and control the speed of the scooter whilemaintaining both hands on the handlebar 26. The acceleration handle 164may be fastened to either side of the handlebar 26. In alternateembodiments the acceleration handle 164 can be attached to other areasof the scooter or the acceleration handle 164 may be in the form of afoot peddle located on the platform 10 or any other convenient locationof the scooter.

[0053] In most instances, the user may slow the speed of the scooter byreleasing the acceleration handle 164. As previously mentioned,releasing the handle 164 causes the roller 116 to stop driving thescooter. In fact, the roller 116 will provide a small braking force. Therear wheel 14 must be able to overcome the frictional force of the motorshaft 135 and pulley system to keep rotating. However, sometimes thisbraking force will not be sufficient to bring the scooter to a completestop. For example, if the rider is traveling down a steep hill thescooter may continue to accelerate even though the acceleration handle164 has been released. Similarly, if the rider needs to bring thescooter to a quick stop, releasing the acceleration handle 164 may notstop the scooter in a sufficiently short period of time.

[0054] The foot brake 16 provides an additional method to stop or slowthe scooter. Stepping on the foot brake 16 brings the underside of thefoot brake 16 in contact with the rear wheel 14. This contact will slowthe rotation of the rear wheel 14 and eventually bring it to a completestop. In one embodiment, when the foot brake 16 is depressed, a motorcut-off switch interrupts the electrical signal to the motor 114 aspreviously mentioned, and electrically isolates the motor from thebattery 156. The switch prohibits the motor shaft from driving theroller 116 while the foot brake 16 is depressed, even if the handle 164is pulled towards the handlebar 26. This prevents the motor assembly 106from driving the rear wheel 14 while the foot brake 16 is inhibitingrotation of the rear wheel 14. If the foot brake 16 did not include acutoff switch, the motor shaft 135 could continue to attempt to rotatethe roller 116 even though rotation of the rear wheel 14 is beinginhibited by the foot brake 16. This could overheat and/or overload themotor 114, reducing the life of the motor or damaging it permanently.Furthermore, switch will be in an open position when the scooter is in a“free wheel” mode. Thus, electrical power will not be transmitted to themotor when the scooter is in “free wheel” mode (see also switch 804 inFIG. 9).

[0055]FIG. 8 is an alternate embodiment of the motor assembly 106. Inthe embodiment shown in FIG. 8, the motor assembly is inboard of thescooter rear wheel 14 rather than above or behind the rear wheel 14 ofthe scooter as described in the embodiment shown in FIGS. 2-7. In theembodiment shown in FIG. 8, the motor assembly 106 is rigidly fixed tothe footboard 10 of the scooter, but does not interfere with the footbrake 16. In the embodiment shown in FIG. 8, the foot brake 16 alsoincludes a pin 802 that extends from one side of the foot brake 16. Whenthe foot brake 16 is in its inactive (non-depressed) position, the pin802 is in contact with a switch lever 804 that is associated with themotor assembly 106 which closes the circuit and allows electrical powerto be delivered to the motor assembly 106. When a user engages the footbrake 16 by depressing it, the pin 802 is moved out of contact with theswitch lever 804 thus creating an open circuit and preventing deliveryof electrical power to the motor assembly 106 and preventing the motorassembly 106 from driving the rear wheel 14.

[0056]FIG. 9 shows an elevation view of the motor assembly 106 attachedto the scooter shown in FIG. 8. In the embodiment shown in FIG. 9, whenthe foot brake 16 is in an inactive position (non-depressed), it is heldout of contact with the wheel 14 by a torsional spring 902. Thetorsional spring 902 is wound around a brake axle 904 and biased againstboth the foot brake 16 and at least one platform 906 on the rear fork30. In alternate embodiments, the foot brake 16 may be supported byother mechanisms known in the art or the torsional spring 902 may bebiased against other sections of the scooter.

[0057] As described with regards to FIG. 8, when foot brake 16 is in aninactive position (non-depressed), the pin 802 is held in contact withthe switch lever 804. However, when the foot brake is depressed, the pin802 is moved out of contact with the switch lever 804 and electricalpower is not delivered to the motor assembly 106 to drive the wheel 14.It is noted that the foot brake 16 is located aft of the motor 106 forconvenience of operation. The user can rest his rear foot on the motorand when desired conveniently shift his rear foot aft to activate thefoot brake.

[0058] In the embodiment shown in FIG. 9, the motor assembly 106 ispivotally mounted on a rotation axle 908. The rotation axle 908 isconnected to a support bracket 910 that is rigidly fixed to the scooter.In the embodiment shown in FIG. 9, the support bracket 910 is mounted tothe scooter and primarily supported on the brake axle 904. To preventrotation of the support bracket 910 and motor assembly 106 around therotation axle 908, a front portion of the support bracket 910 restsagainst the upper surface of the foot board 10 and a rear portion 912 ofthe support bracket 910 rests on the upper side of the rear fork 30. Inthe embodiment shown in FIG. 9, the front and rear portions of thesupport bracket are biased by a torsional spring such that downwardpressure is applied to both the rear fork 30 and the upper surface ofthe foot board 10. In alternate embodiments, the support bracket may befixed to the scooter in various other manners.

[0059] In the embodiment shown in FIG. 9, the motor assembly 106 isbiased by a torsional spring (not shown) such that the friction brushing(not shown) is pressed against the wheel 14. However, in alternateembodiments other methods know in the art to hold the roller (not shown)in contact with the wheel 14 may be used.

[0060] The motor assembly 106 further includes a toggle locking pin 914.The toggle locking pin 914 allows the motor assembly 106 to be movedfrom a first position to a second position and held in the secondposition. In a first position, the roller (not shown) is pressed againstthe wheel 14 such that rotation of the roller (not shown) can drive thewheel 14 and propel the scooter. In a second position, the roller (notshown) is held away from the wheel 14, thus allowing the scooter to beused without assistance from the motor assembly 106. In the embodimentshown in FIG. 9, when the motor assembly 106 is in a second position,the toggle pin 914 (FIGS. 11, 12) can engage a bore (not shown) in themounting bracket such that the motor assembly is held in the secondposition. In one embodiment, the toggle pin 914 is spring biased suchthat when the toggle pin 914 is moved in a prescribed manner, the springbias of the toggle pin 914 will drive it into the bore (not shown) inthe mounting bracket when the motor assembly is in the second position.The toggle pin 914 may then be manually or automatically removed fromthe bore (not shown) so that the motor assembly may return to the firstposition.

[0061]FIG. 10 is a cross-sectional view of the motor assembly 106 andscooter shown in FIGS. 8 and 9. In the embodiment shown in FIG. 10, themotor assembly contains a roller 116 to frictionally drive the wheel 14and a motor 114 to convert received electrical power into mechanicalpower to drive the roller 116. FIG. 10 also shows that the brake 16further includes a brake pad 1002. In the embodiment shown in FIG. 10,the brake pad is removably attached to the brake 16 by two fasteners1004. However, in alternate embodiments, the brake pad may not bepresent, or may be fixedly attached to the brake 16.

[0062]FIG. 11 is a perspective view of the interior of the motorassembly 116 shown in FIGS. 8-10. In the embodiment shown in FIG. 11 themotor 114 includes a drive wheel 1102 that is connected to the drivespindle 1104 of the motor 114. The drive wheel 1102 is affixed to thedrive spindle 1104 such that it rotates with the same angular velocityas the drive spindle 1104 with little or no slippage. A drive belt 1106connects the drive wheel 1102 to a roller driver 1108. The drive belt1106 frictionally engages both the drive wheel 1102 and the rollerdriver 1108. The rotation of the roller driver 1108 rotates roller 116about a roller axis 1110 which remains essentially stationary relativeto the scooter. The roller 116 frictionally engages the wheel 14 todrive the scooter. The embodiment shown in FIG. 11 also includes asecond roller 1112 which is removably attached to the roller axis 1110and the roller 116. The second roller 1112 is a spare roller that may beinterchangeably switched with the roller 116. In the embodiment shown inFIG. 11, an end cap 1114 that is removably attached to the roller axis1110.

[0063]FIG. 11 further shows an embodiment which includes a bias spring1116 that is associated with the toggle pin 914. The bias spring 1116may be engaged such that the toggle pin 914 will be driven into a bore(not shown) in the mounting bracket 910 when the motor assembly 116 isin a second position, as described above with regards to FIG. 9.

[0064]FIG. 12 shows a perspective view of discrete components of oneembodiment of the motor assembly 116. The embodiment shown in FIG. 12includes a keyed spindle 1202 that mounts on the roller axis 1110 and isfree to rotate about the roller axis 1110. The keyed spindle 1202 has apredetermined pattern that allows it to engage the bore within theroller 116 such that the keyed spindle 1202 can drive the roller 116.The keyed spindle 1202 is also designed to mate with a first driver cam1204 and a second driver cam 1206. The opposite side of the first drivercam 1204 is keyed to mate with the roller driver 1108 and the oppositeside the second driver cam 1206 is keyed to mate with and degage thebore of the second roller 1112. A locking cam 1208 is keyed to mate withthe portion of the second driver cam that passes through the bore of thesecond roller 1112 and engage the end cap 1114. In the embodiment shownin FIG. 12, rotation of the roller driver 1108 causes rotation of thefirst driver cam 1204, the keyed spindle 1202, the roller 116, thesecond driver cam 1206, the second roller 1112, the locking cam 1208 andthe end cap 1114 about the roller axis 1110.

[0065] In the embodiment shown in FIG. 12, the individual components maybe easily removed by a user and replaced when worn or damaged. Forexample, if the roller 116 becomes worn, a user may wish to exchange theroller 116 with the second roller 1112. The user may simply remove theend cap 1114, locking cam 1208, second roller 1112 second driver cam1206, roller 116, drive spindle 1202 and first driver cam 1204. The usermay then disassemble the part and reassemble them with the roller 116and second roller 1112 in the opposite locations then reinsert theassembly back along the roller axis 1110 and begin using the scooteragain. Similarly, a user my replace any other worn or damaged pieceassociated with the drive spindle 1202.

[0066] Although FIG. 12 describes a configuration in which allcomponents coaxial with the roller axis 1110 rotate when the rollerdriver 1108 is rotated, in alternate embodiments one or more componentsthat are coaxial with the roller axis 1110 may remain rotationallystationary when the roller driver 1108 is rotated, provided that theroller 116 rotates in a predetermined relationship to the roller driver1108. For example, in one embodiment, the second roller 1112 may remainrotationally stationary when the roller driver 1108 is rotated.Furthermore, in alternate embodiments, the second driver cam 1206 thatengages the second roller 1112 may be rotationally isolated from thedriver spindle 1202 by ball-bearing-type isolation between the side thatengages the drive spindle 1202 and the side that engages the secondroller 1112. Thus, rotation of the drive spindle 1202 would not forcerotation of the second roller 1112, the locking cam 1208 or the end cap1114.

[0067] In yet another alternate embodiment, the side of the seconddriver cam 1206 that engages the second roller 1112 may not be keyed inthe area in which the second roller is engaged. Thus, rotation of thesecond driver cam 1206 would not force rotation of the second roller1112.

[0068] To install the embodiment of the motor assembly 104 shown inFIGS. 8-11, a user can remove the brake axle 904 and the existing footbrake 16. The support bracket 910 together with the motor assembly 104can then be positioned on the foot board 10 such that the rear portion912 of the support bracket 910 rests on the rear fork 32 and the forwardportion of the support bracket 910 rests on the rear end of the footboard 10. The pivotal supports of the new foot brake 16 can then bealigned with the new support bracket along the axis from which the brakeaxle 904 was removed. The brake axle 904 can then be re-inserted in itsoriginal location of the scooter to secure the new foot brake 16,support bracket 910, and motor assembly 104 to the scooter. The user canthen tension the torsional spring against the new foot brake 16 suchthat the foot brake 16 is held out of contact with the rear wheel 14.The battery 156 and throttle control 164 can then be attached to thescooter in various locations and in various manners. The motor assembly104, battery 156 and throttle control 164 can then be electricallyconnected as desired.

[0069]FIG. 13 is a perspective view of a battery 1302 that is beingmounted on the connecting bar 22 of a scooter. In the embodiment shownin FIG. 13, the battery 1302 has a mounting slot 1304 and a bore 1306.The scooter has a mounting track 1308 that is removably attached to theconnection bar 22 of the scooter by fasteners 1310 that frictionallyretain the mounting track in position on the connection bar 22. Inalternate embodiments, the mounting track 1308 may also be designed tomate with a particular section of the connection bar 22 in a “pocketfit” manner. In the embodiment shown in FIG. 13, the mounting track 1308had a locking lever 1312 that extends from the side of the mountingtrack 1308. In one embodiment, the mounting track 1308 may include a setof contact plates that are designed to electrically connect the battery1302 to the mounting track 1308 which is connected to both the motorassembly 106 and the throttle assembly 160 to deliver power to the motorassembly 106. In an alternate embodiment, the battery 1302 may bedirectly connected to the motor assembly 106 and the throttle assembly160 and electrically isolated from the mounting track 1308.

[0070]FIG. 14 is a perspective view of the battery 1302 shown in FIG. 13attached to the mounting track 1310. In the embodiment shown in FIG. 14,the locking lever extends through the bore 1306 in the battery 1302 toretain the battery 1302 in position relative to the mounting track 1310.Thus, in the embodiment shown in FIG. 14, to disengage the battery 1302from the mounting track 1310, the locking lever 1312 must be depressed.In alternate embodiments, various other mechanisms know in the art maybe used to secure the battery 1302 to the mounting bracket 1310.

[0071] With respect to each of the above two embodiments, the motorassembly and the battery are robustly, but removably secured to thescooter.

[0072] The foregoing description of embodiments of the present inventionhas been provided for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise forms disclosed. Obviously, many modifications and variationswill be apparent to the practitioner skilled in the art. The embodimentswere chosen and described in order to best explain the principles of theinvention and its practical application, thereby enabling others skilledin the art to understand the invention for various embodiments and withvarious modifications that are suited to the particular usecontemplated. It is intended that the scope of the invention be definedby the following claims and their equivalents.

1. A device that can electrically power a push scooter having afootboard mounted between a front wheel and a rear wheel, a steeringhandle operably associated with the front wheel, and a foot brake thatcan brake the rear wheel, comprising: a motor assembly including a motorand a roller adapted to selectively frictionally engage and drive therear wheel of the scooter; said motor assembly movably mounted above andbetween the rear wheel and the foot board; and with the foot brakelocated aft of the motor assembly.
 2. The device as recited in claim 1,wherein said roller is selectably engaged with the rear wheel in apower-assist position and is selectably disengageable from the rearwheel in a free-wheel position.
 3. The device of claim 2 including alever for selectively locking the motor and the roller in one of thepower-assist position and the free-wheel position.
 4. The device asrecited in claim 1, wherein said device further includes a cutoff switchthat electrically isolates said motor from a battery when the foot brakeis depressed, preventing said motor from driving said roller while thefoot brake is depressed.
 5. The device as recited in claim 4, whereinsaid cutoff switch is actuated by relative motion between the foot brakeand the motor assembly.
 6. The device of claim 1 wherein said motorassembly is adapted to be movable by use of the foot of a rider from aposition where the roller engages the rear wheel to a position where theroller disengages the rear wheel.
 7. A device that can electricallypower a push scooter having a footboard mounted between a front wheeland a rear wheel, a steering handle operably associated with the frontwheel, and a foot brake for braking the rear wheel, the foot brakepivotally mounted to said footboard by a foot brake mount, comprising: amotor assembly including a motor and a roller adapted to selectivelyfrictionally engage and drive the rear wheel of the scooter; and saidmotor mounted by the foot brake mount to the scooter and forward of thefoot brake.
 8. The device as recited in claim 7, wherein said roller canbe selectively placed into a rear wheel engaging power-assist positionand a rear wheel disengaged free-wheel position.
 9. The device asrecited in claim 7, wherein said device further includes a cutoff switchthat electrically isolates said motor from a battery when the foot brakeis depressed, preventing said motor from driving said roller while thefoot brake is depressed.
 10. The device as recited in claim 9, whereinsaid cutoff switch is activated by relative motion between the footbrake and the motor assembly.
 11. A device that can selectablyelectrically power a push scooter having a footboard mounted between afront wheel and a rear wheel, a steering handle operably associated withthe front wheel, and a foot brake, comprising: a battery; a motorassembly including a motor and adapted to frictionally engage and drivethe rear wheel of the scooter; and a bracket mechanically connected tothe scooter, that supports said motor assembly behind the rear wheel andthat supports the battery above the motor assembly and behind the rearwheel.
 12. The device as recited in claim 11, wherein said motor has aroller that can be placed in a power-assist position and a free-wheelposition with regard to the rear wheel.
 13. The device of claim 11wherein said rear wheel is mounted to the footboard with a mountingframe and the bracket is adapted to mount onto said mounting frame. 14.An electrically powered vehicle, comprising: a scooter having afootboard mounted between a front wheel and a rear wheel, a steeringhandle operably associated with said front wheel, and a foot brake thatcan selectively brake the rear wheel; a motor assembly connected to saidscooter for electrically powering said scooter, said motor assemblyhaving a roller for selectively frictionally engaging and driving saidrear wheel of said scooter; a mounting bracket for pivotally mountingsaid motor to the scooter with the motor assembly located between andabove said rear wheel and said footboard of said scooter and with thefoot brake located aft of the motor assembly; and a throttle assemblythat can selectively control the speed of said roller, which throttleassembly is mounted on said steering handle.
 15. The vehicle as recitedin claim 14, wherein said vehicle further includes a cut-off switch thatshuts off said motor when the foot brake is depressed.
 16. Anelectrically powered vehicle, comprising: a scooter having a footboard,a front wheel, a rear wheel operably associated with said footboard by arear fork, a steering handle operably associated with said front wheel,and a foot brake that can selectively brake the rear wheel; a devicethat can selectively electrically power said scooter, including: abattery; a motor assembly including a motor that is electricallyconnected to said battery and a roller for frictionally engaging anddriving said rear wheel; a mounting bracket mechanically connected tosaid rear fork for supporting said motor assembly behind the rear wheeland said battery above the motor assembly and above the rear wheel; anda throttle assembly electrically connected to said battery and saidmotor and that can selectively control the speed of said roller, saidthrottle assembly mounted to said steering handle.
 17. A method ofretrofitting a push scooter with a propulsion system comprising thesteps of: removing a rear wheel axle from a rear fork of the pushscooter; attaching a mounting bracket on the rear fork of said scooterusing the rear wheel axle; having a motor assembly mounted on themounting bracket such that a roller of said motor assembly canselectively frictionally engage a rear wheel that is mounted on the rearwheel axle; and removably attaching a battery to one of said pushscooter and mounting bracket.
 18. A method of retrofitting a pushscooter having a rear wheel and footboard with a propulsion systemcomprising the steps of: removing a brake axle of the push scooter;attaching a mounting bracket on the rear fork of said scooter using thebrake axle; having a motor assembly mounted on the mounting bracket suchthat a roller of said motor assembly can selectively frictionally engagethe rear wheel of said push scooter; and removably securing a battery topower the motor assembly.
 19. A device that can electrically power apush scooter having a footboard mounted between a front wheel and a rearwheel, a steering handle operably associated with the front wheel, and afoot brake movably mounted to the scooter so that the foot brake canbrake the rear wheel, comprising: a motor assembly including a motoradapted to selectively frictionally engage and drive the rear wheel ofthe scooter; and said motor assembly mounted between and above the rearwheel and the footboard with the foot brake located rearwardly of saidmotor assembly and above the rear wheel so that the foot brake can moverelative to a position further rearwardly of said motor in order tobrake rear wheel.
 20. The device of claim 19 wherein: said motor andsaid foot brake are mounted at about the same height above the scooterso that both are adapted to be actuated by the foot of a user.
 21. Thedevice of claim 19 wherein: the motor assembly is movably mounted to thescooter, with the motor assembly having a first rear wheel engagingposition and a second rear wheel disengaged position, and said motorassembly is located adjacent to the foot brake so that both are adaptedto be actuated by the foot of a user.
 22. A device that can electricallypower a push scooter having a footboard mounted between a front wheeland a rear wheel, a steering handle operably associated with the frontwheel, and a foot brake pivotally mounted to the scooter so that thefoot brake can brake the rear wheel, comprising: a motor assemblypivotally mounted to the footboard including a motor adapted toselectively frictionally engage and drive the rear wheel of the scooter,with the motor pivotable between a rear wheel engaging position and arear wheel disengaged position; and said motor assembly mounted betweenand above the rear wheel and the footboard with the foot brake locatedrearwardly of said motor assembly and above the rear wheel so that thefoot brake can move relative to a position further rearwardly of saidmotor in order to brake rear wheel.
 23. The device of claim 22 wherein:said motor and said foot brake are mounted at about the same heightabove the scooter so that both are adapted to be actuated by the foot ofa user.
 24. A retrofit kit adapted to be fitted to a push scooter toelectrically power the push scooter, where the push scooter has afootboard mounted between a front wheel and a rear wheel, a steeringhandle operably associated with the front wheel, and a foot brakemovably mounted to the scooter so that the foot brake can brake the rearwheel, the retrofit kit comprising: a battery; a motor assemblyincluding a motor adapted to selectively frictionally engage and drivethe rear wheel of the scooter; and a mount that enables said motorassembly to be mounted between and above the rear wheel and thefootboard with the foot brake located rearwardly of said motor assemblyand above the rear wheel so that the foot brake can move relative to aposition further rearwardly of said motor in order to brake rear wheel.25. A retrofit kit adapted to be fitted to a push scooter toelectrically power the push scooter, where the push scooter has afootboard mounted between a front wheel and a rear wheel mounted to thefootboard with a mounting fork, a steering handle operably associatedwith the front wheel, and a foot brake movably mounted to the scooter sothat the foot brake can brake the rear wheel, the retrofit kitcomprising: a battery; a motor assembly including a motor adapted toselectively frictionally engage and drive the rear wheel of the scooter;and a mount that enables said motor assembly to be mounted onto themounting fork and behind the rear wheel and with the battery locatedabove the motor assembly and behind the foot brake.